.content {
  width: 100%;
  height: 700px;
  position: relative;
}

.content .cen_btn {
  position: fixed;
  bottom: 30px;
  width: 30%;
  height: 70px;
  background: paleturquoise;
  margin-top: -70px;
  margin-left: 20px;
}

@keyframes moveX {
  0% {
    left: -100px;
  }
  100% {
    left: 80%;
  }
}

@keyframes moveY {
  0% {
    top: 10%;
  }
  100% {
    top: 60%;
  }
}

@keyframes moveScale {
  0% {
    transform: scale(0.6);
  }
  50% {
    transform: scale(1);
  }
  100% {
    transform: scale(0.6);
  }
}

.boxItem {
  position: absolute;
  width: 200px;
  height: 200px;
  top: 100px;
  left: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  color: aliceblue;
  animation-name: moveX,moveY,moveScale;
  animation-direction: alternate;
  animation-duration: 10s ,10s ,20s;
  animation-iteration-count: infinite;
  animation-timing-function: cubic-bezier(0.445, 0.05, 0.55, 0.95);
}
